, cpc_count_sys_events

Synopsis

Description

In certain applications, it can be useful to explicitly enable and disable performance
counters at different times so that the performance of a critical algorithm can
be examined. The cpc_count_usr_events() function can be used to control whether events
are counted on behalf of the application running in user mode, while cpc_count_sys_events() can
be used to control whether events are counted on behalf of the
application while it is running in the kernel, without otherwise disturbing the binding of
events to the invoking LWP. If the enable argument is non-zero, counting of
events is enabled, otherwise they are disabled.

Return Values

Upon successful completion, cpc_count_usr_events() and cpc_count_sys_events() return 0. Otherwise, the functions return -1
and set errno to indicate the error.

Errors

The cpc_count_usr_events() and cpc_count_sys_events() functions will fail if:

EAGAIN

The associated performance counter context has been invalidated by another process.

EINVAL

No performance counter context has been created, or an attempt was made to enable system events while delivering counter overflow signals.

Examples

Example 1 Use cpc_count_usr_events() to minimize code needed by application.

In this example, the routine cpc_count_usr_events() is used to minimize the amount of
code that needs to be added to the application. The cputrack(1) command can
be used in conjunction with these interfaces to provide event programming, sampling, and
reporting facilities.

If the application is instrumented in this way and then started by
cputrack with the nouser flag set in the event specification, counting of user
events will only be enabled around the critical code section of interest.
If the program is run normally, no harm will ensue.

See Also

Notes

The cpc_count_usr_events() and cpc_count_sys_events() functions exist for binary compatibility only. Source containing these
functions will not compile. These functions are obsolete and might be removed in
a future release. Applications should use cpc_enable(3CPC) instead.